The case for treatment of selected patients with primary pulmonary hypertension.

The treatment of primary pulmonary hypertension with pulmonary vasodilator agents is controversial. Some patients have benefited, while others have not. To shed light on the mater we reviewed published reports of 117 patients having acute vasodilator challenge and found that 53 reduced their pulmonary vascular resistance by 30% or more. Calcium antagonists (n = 46), hydralazine (n = 23), and diazoxide (n = 18) gave approximately equivalent acute reductions in resistance (30%, 35%, 32%, respectively), but captopril (n = 17) gave a poor response (-7%). The reports indicated that chronic treatment (3 months or longer) benefited only 4 of 64 patients (6%) having acute reduction in resistances of less than 30%. However, when resistance was lowered acutely by more than 30%, 33 of 53 patients (62%) improved with treatment. In 5 patients having multiple catheterization, improvement was sustained for the duration of follow-up (10 to 48 months). Except for captopril, the agents employed gave similar reductions in resistance, and perhaps the choice should be determined by avoidance of side-effects. Long-term benefit is never certain, but selecting patients with brisk acute vasodilator responses may predict the benefit from chronic vasodilator treatment.